The natural frequencies of translational motion for the first two modes in each direction have been experimentally measured and computed analytically for two tall reinforced concrete shear wall buildings. For the first building, the frequencies were measured from ambient as well as man-excited data. The critical damping ratios were also estimated from the decay of the man-excited accelerograms. For the second building, the frequencies were estimated from ambient response data. The computer generated analytical models yielded reasonably satisfactory estimates for the fundamental frequencies for Building 1, but for Building 2, the estimated frequency in the longitudinal direction did not agree with its measured value.